So far, it has been known in the art that sialic acid is present in many animal bodies and on the cell surface of several bacteria as a sialylated molecular complex, for example, glycoprotein, glycolipid, oligosaccharide or polysaccharide.
Recently, this compound has been thought to be important medicinally and pharmaceutically for nerve function, cancer, inflamation, immunity, viral infection, differentiation, hormone receptor, and others. Further, much attention has been paid to this compound as a peculiar active substance located on the cell surface. However, the role of sialic acid in the sialylated molecular complex has not yet been ascertained.
Furthermore, this compound has been studied by many natural organic chemists and many kinds of derivatives thereof have been obtained. However, no derivatives having a remarkable physiological activity have been obtained yet.
Further, the average span of human life has been indeed extended by various improvements in medical treatment of malignant tumor of hematopoietic organ, many kinds of cancers, and collagen disease. However, these improvements have inevitably increased use of medicines such as adrenal cortical hormone, immunosuppressant, etc. Therefore, a number of undersirable side effects such as decrease in immunological competence have arisen.
The present inventors have paid special attention to sialic acid which is a bio-inherent component and have made intensive studies on immuno-controlling agents which have substantially no side effects and exhibit a controlling activity for immunological surveillance and are obtained by chemically modifying sialic acid. As a result, the present inventors have prepared sialosyl cholesterol which is useful as a neuropathy remedy. This is based on the finding that the present sialosyl cholesterol promotes growth of the neurites of neuroblastoma cells derived from mouse (Neuro 2a), when the activity of the sialosyl cholesterol is examined by adding it to the culture of Neuro 2a.
The object of the present invention is to provide a new sialosyl cholesterol.
Another object of the present invention is to provide a new process for producing sialosyl cholesterol.
Another object of the present invention is to a new neuropathy remedy.
Incidentally, since the present sialosyl cholesterol is present in an Na salt form, the cholesterol has an excellent water-solubility and makes the utility of the cholesterol wider.